Replace spoke or get a new wheel? (road/commuter)

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Replace spoke or get a new wheel? (road/commuter)

Postby 78alex » Wed Nov 21, 2012 10:11 am

I've just broken a spoke on my rear wheel (a 32 spoke Alexrim DA22 32 spoke). Going about 40 km/h down a moderately smooth road, when I heard the loud popping sound.
Bike is about 7 years old, I weigh 93kg. It's the second spoke to go on the wheel in about 500km and it's now fairly warped.

Worth replacing the spoke and truing the wheel again, or get a new wheel in the $50-$100 range? Is wear and tear or metal fatigue becoming an issue at this stage?
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by BNA » Wed Nov 21, 2012 1:23 pm

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Re: Replace spoke or get a new wheel? (road/commuter)

Postby jasonc » Wed Nov 21, 2012 1:23 pm

if they are 700c go the pro-lite como. over 7000kms on mine. cheap heavy and tough.
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby ironhanglider » Wed Nov 21, 2012 6:19 pm

78alex wrote:I've just broken a spoke on my rear wheel (a 32 spoke Alexrim DA22 32 spoke). Going about 40 km/h down a moderately smooth road, when I heard the loud popping sound.
Bike is about 7 years old, I weigh 93kg. It's the second spoke to go on the wheel in about 500km and it's now fairly warped.

Worth replacing the spoke and truing the wheel again, or get a new wheel in the $50-$100 range? Is wear and tear or metal fatigue becoming an issue at this stage?


I'm not convinced that there is good value in sub $100 new wheels.

The cheapest option is to buy a spoke and a tool and learn something about wheels. It is not the black art that people make it out to be and there are lots of resources around including here to help you. Spokes come in different lengths measured from the inside of the elbow to the very end (including the threads).

It is likely that the spoke which broke did so at the elbow. I'm also guessing that it is on the non-drive side. There should be enough of the spoke left to be able to measure the length to the nearest millimetre.

Replace the spoke and stress relieve all of them*. If you do this there is a good chance that you will fix the problem. Iff you continue to break spokes then buying the rest of the set of 16 would be the next cheapest option.

Cheers,

Cameron

*Stress relief = grab each spoke and the one nearest parallel to it on the same side and try to squeeze them together hard. Do all 8 pairs on each side.
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby 78alex » Wed Nov 21, 2012 8:03 pm

Thanks Cameron, I'll give it a shot and cross my fingers the truing goes OK. Can you recommend a site or video?
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby ironhanglider » Fri Nov 23, 2012 9:36 am

78alex wrote:Thanks Cameron, I'll give it a shot and cross my fingers the truing goes OK. Can you recommend a site or video?


I know that you're not building a whole wheel yet but read this anyway. It will help to have the whole picture.

http://sheldonbrown.com/wheelbuild.html

It will help greatly to be able to pull the cogs (cassette or freewheel) off your wheel. You will also need to remove the tyre, tube and rim tape.

Note that there are four different types of spokes on wheels where the spokes cross each other(left side, right side, pulling and pushing). You will notice that on the hub flange in most instances the spokes will alternate with heads in or heads out. Insert your new spoke in the hub in the correct orientation and match the pattern of the similar type spokes ie cross over two and under one or vice versa. If the new spoke is the right length it will just reach to the spoke hole in the rim. Make sure you have greased the thread on the spoke then put the nipple on and tighten it up with a spoke key.

The tensioning and truing, and stress relieving sections of the Sheldon guide will be useful here. In theory if you have just broken one spoke you can bring the replacement up to the same tension and it will bring the wheel straight again. Unfortunately it doesn't always work like this. Besides there is a good likelihood that other spokes have changed tension when the wheel was ridden when out of true.

Cheers,

Cameron
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby jacks1071 » Fri Nov 23, 2012 12:08 pm

If you've done two spokes in a short time period some of the issues could be:

1. Spokes are all fatigued
2. Spoke tension is uneven
3. Rim maybe bent (in which case even spoke tension will be impossible).
4. A combination of all of the above.

The only guaranteed way to fix it will be to re-build the wheel with new spokes (after checking that the rim is not bent), you could back the tension off and re-tension the whole wheel as it is which might get it reliable - depends how much you want to mess around with it.

Or you can start fresh with something new and know its going to be reliable without any hassel.
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby 78alex » Fri Nov 23, 2012 12:59 pm

Thanks again Jacks & Cameron! The Sheldon Brown wheel article seems to be a bit of a reference. I'll give it a go, just replacing and adjusting the one spoke.
Failing that I'll do the walk of shame- into the bike shop with a failed DYI.
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Re: Replace spoke or get a new wheel? (road/commuter)

Postby drubie » Fri Nov 23, 2012 5:59 pm

jacks1071 wrote:If you've done two spokes in a short time period some of the issues could be:
...
Or you can start fresh with something new and know its going to be reliable without any hassel.


My personal limit is 4 spokes before pulling the wheel down and retensioning it - I always figured that the first spoke that goes will generally weaken 1 other, so I would expect the wheel to settle down after two spokes.

if it doesn't, then replace, detension and start again. I've got a tandem rear wheel in my care that was popping spokes with monotonous regularity - the tear down showed that at some point the chain had over shifted onto the inside of the cassette and gouged the spokes, making them all weak. I replaced the worst of it and it definitely settled down but not before a pretty careful re-tension.

two spokes to me is pretty normal though. Anything more than that would provoke suspicion.
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